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Global Translational Medicine Graphene oxide in cancer drug delivery applications

based materials are distinguished by their exceptional control to prevent the formation of explosive by-products,
physicochemical properties, including high surface followed by extensive washing to remove residual acids
area, biocompatibility, and versatile functionalization and impurities. Brodie’s method yields a greater relative
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capabilities. Such properties make GO and rGO highly quantity of hydroxyl groups and achieves a more uniform
7,8
suitable for drug delivery and theranostics, an integrated distribution of functional groups across the planar surface
method that combines therapy and diagnostics to offer of GO flakes. However, despite its historical significance,
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more individualized cancer treatment. 9 Brodie’s method has limitations, including the use of
The capacity of GO and rGO to efficiently transport and hazardous chemicals and the generation of toxic gases,
administer concentrated therapeutic substances directly to which pose significant safety and environmental concerns.
tumor sites, coupled with their adjustable surface chemistry 2.2. Staudenmaier’s method
for controlled drug release, represents noteworthy progress
in the field of cancer treatment. Moreover, the distinctive Staudenmaier’s method is a modification of Brodie’s
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optical qualities of GO make it well-suited for applications method, wherein graphite is oxidized using a mixture of
in photothermal and photodynamic therapies, further concentrated sulfuric acid (H₂SO₄), HNO₃, and KClO₃ in
augmenting its therapeutic efficacy. 11 a solitary container. This modification improves both the
efficiency and safety of the process. Constant agitation
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This mini-review aims to provide a comprehensive of the reaction mixture ensures complete oxidation,
summary of recent advancements in the utilization of GO followed by thorough washing to eliminate any remaining
and rGO for cancer drug delivery and theranostic purposes. acids and by-products. While Staudenmaier’s method
In this article, we discuss the latest research findings, key minimizes certain risks inherent in Brodie’s method, it
developments, challenges, and future prospects in this still necessitates the handling of hazardous chemicals and
rapidly evolving field, exploring the potential of GO and careful supervision to prevent the generation of deadly
rGO to revolutionize cancer treatment and diagnosis. fumes, such as toxic chlorine gas, which poses safety
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2. Synthesis of GO issues. Despite these challenges, Staudenmaier’s method
represents a notable advancement in the synthesis of GO.
Several methods are available for synthesizing GO, each
with its own set of advantages and disadvantages. The most 2.3. Hummers’ method
common methods include Brodie’s method, Staudenmaier’s Due to its efficacy and simplicity, the Hummers’ method
method, Hummers’ method, and Tour’s method (Table 1). remains pivotal in GO synthesis. This method involves
the oxidization of graphite powder using a mixture of
2.1. Brodie’s method potassium permanganate (KMnO₄) and sodium nitrate
Brodie’s method, one of the earliest techniques established in concentrated H₂SO₄, with careful temperature control
for synthesizing GO, involves the oxidization of graphite to prevent overheating. After oxidation, the mixture is
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with potassium chlorate (KClO₃) in fuming nitric acid diluted with water, and hydrogen peroxide is added to
(HNO₃). This exothermic reaction requires careful reduce any remaining manganese oxides. The product is

Table 1. Advantages and disadvantages of different graphene oxide (GO) synthesis methods
Methods Advantages Disadvantages
Brodie’s Method i. A traditional method for synthesizing GO composites. i. Requires careful control of the exothermic reaction to
ii. Produces a higher relative quantity of hydroxyl groups, resulting in a prevent explosive by-products.
more uniform distribution of functional groups across the GO flakes’ ii. Involves hazardous chemicals that generate toxic gases,
planar surface. posing safety and environmental concerns.
Staudenmaier’s Potassium chlorate acts as a catalyst for the oxidation reaction, leading to The process generates toxic chlorine gas, raising
method increased yields of GO. significant safety concerns.
Hummers’ i. Produces GO with higher concentrations of oxygen functional groups Harsh reaction conditions, such as high temperature and
method (hydroxyl, carboxyl, and epoxy groups), enhancing hydrophilicity and the use of strong acids (e.g., H₂SO₄), present significant
allowing for surface modification. drawbacks.
ii. Yields GOs with a high specific surface area, making them ideal for
applications in adsorption and catalysis.
Tour’s method i. Facilitates controlled and precise functionalization, introducing various The method is labor-intensive and involves multiple steps,
functional groups onto the surface of GO. making it a more complex process.
ii. GOs generated through this method demonstrate enhanced stability
against aggregation and restacking in comparison to other methods.

Volume 3 Issue 3 (2024) 2 doi: 10.36922/gtm.4602